1. Field of the Invention
The invention relates to a device for holding a rotary element stationary relative to a fixed body.
The invention has been devised, particularly but not exclusively, for the purpose of holding a camshaft or a fuel injection pump of an internal combustion engine stationary relative to an engine casing. Commonly, a camshaft or fuel injection pump is driven in timed relation to the engine crankshaft by a toothed drive belt (timing belt) or chain entrained around toothed pulleys or sprockets (hereafter referred to as sprockets) on the crankshaft and the drive shaft of the camshaft or fuel injection pump. In order to prevent failure in service and possible engine damage, service schedules usually specify that the timing belt be replaced at predetermined time and/or mileage intervals. It is essential, when removing the timing belt for any reason, to ensure that the timing relationship between the camshaft or fuel injection pump and the crankshaft is not lost. Therefore it is desirable to hold the camshaft and/or fuel injection pump against rotation relative to the engine casing whilst the old timing belt is removed and a new timing belt fitted.
2. Description of the Prior Art
Service tools for holding camshafts and/or fuel injection pumps against rotation are known, but as supplied by motor manufacturers they are usually specifically designed for one engine or family of engines and are not usable for other engines. If a service establishment wishes to perform such work on many different engines, but does not wish to keep a large number of special tools, there is a requirement for a more versatile holding device, which is capable of being used on a wide range of engines.
In our UK Patent No.2340539 a holding device is disclosed for the purpose of holding stationary, relative to one another, the camshafts of a double overhead camshaft internal combustion engine, or a camshaft and a fuel injection pump driving shaft of an engine, e.g. in a motor vehicle. In our U.S. Pat. No. 6,332,256 a holding device is shown for the same purpose as that of the holding device in our UK Patent No.2340539, however the holding device in our U.S. Pat. No. 6,332,256 is multi-adjustable. Neither of these devices address the problem of holding a single rotary element stationary relative to a fixed body.